SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93bedb72a2d116f7410fcd192ff747f0f8ae2b359731549826461d79ddcd022e' 
  AND token = '8dQkN4gh+vmE8aPbnyBUCPezK/wZfBF7SVkBW8q8r2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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