SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c577ddfca745735897cca297dc2eb224573466c922f1dc4e924ac60582840ec3' 
  AND token = 'Lk6fw3De+ODc9GRVpYkW0oJaFTMMGdSfUsyYhNxTfto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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