SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1d14f0017e2d87b3142e6df785620dc0b43927918bacd8aa8e9df623038f9a6' 
  AND token = 'QphyrEAHulJZjlkAEbvceuP+aKVmW2rCIqe4hXqAcs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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