SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4c923d849472796101d6c3a7606f51f21374cd8a20c5dbe7e504dc9bf5e8259' 
  AND token = 'mWLX6Q99e3RO9z/l7t6nRD6oFiCiSj6EPWACglmap2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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