SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29df0fd72898c2e5665534925659636bcf3e4e164f382ae02e1c5196f79477df' 
  AND token = 'HlIjH4GKSc5QPLs/uwKnRF3RCBOiHNeiSgvVQdYQC1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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