SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '955b24c69123d795fee36018611ae18bfb9d6be6e667e09672c1902aeb4e508b' 
  AND token = 'sSWWCdBLakzPpopyRUwlrjIbjpGSgpiCnDIHK3WnnmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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