SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3ae3c275b93e77463f9c7ed3a142162983dfd4769a44b08e310cfba98c473f2' 
  AND token = 'gVdADFT68sN5qbBdCD6b0PTnWtFxkjWDkRACmOeQDX0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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