SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6ef25b542812656140f9957cd212b7911550c22a349d5fb489a9405c7dc9fa7' 
  AND token = 'n7XKXug8vNVJokyloY5zdN9O5qgyOUVLx3eshcNIC8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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