SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb35132be38426261afd1f98798aee58fc0716de583600710f4bf7e7caa32046' 
  AND token = 'C4m9sc4iMZSCJu/a1CepMl8UCX5/j16B+UdcFnwL1q4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}