SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4de84664d2757def562d6b1ef620e2d4d25d3b0b6633bd0f9ac7cf6fcf6743c' 
  AND token = 'sZf1rfok6qL4gxorMglsw003hNnfvi9vICyRaprDzyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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