SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c43e55c41310970768470fcdb013e68cd0ac42396cedb44a3f88c086587adc3e' 
  AND token = '4Qo+9XZM+jL1E1bpIDbxY9DuUFF8MdQDuQ8QTjWzBcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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