SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1138369d6fb3d32860f0ff3a870448883e57b571e237d3ed840eb9f99365f22c' 
  AND token = 'UL+ZR7C/EluJgleYmwhPFaIdSuN8Vahc/MrmmA7fauI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}