SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be9106c686c3ff9037ef2e04292107ce6bb0dc25dfe185d9337eabee8361dc45' 
  AND token = 'VJtntBinGW3uO++/wtmfsARe05GWC2mU+3KELiOYB68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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