SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0530379962328c10b7cd0027f099e2be8502e8bf06a37c04d5f1310deb62594' 
  AND token = 'Pd7UhvD3nUN/OGj9s9AU5QA1ZmnrnUu+r6/b5lnsndA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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