SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3458c5a8b2468afe91e3a0a0691f814825f366edcee8f9358fb4ce0290ac5ed' 
  AND token = 'uayQACcKFL5iwBd2i6g4t6y1mW43CcGE9UfvymQbDmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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