SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '172d174b835437fd7f7df744524833275e0fece480a02beb16808991d2cd555a' 
  AND token = 'ToFyFarN5rA6Zq2eTXcC7sb1zIiBwfxC8fVI10uKTF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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