SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b385f856ae7886589b3767ffd1618635b83d7d8e4609427b3b0b1cf42aa7bd41' 
  AND token = 'pVKm/kNZ0YgH+o6cNrFCxEC3LmuqYy+9KlSXyI0sAd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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