SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cf3abf81403fcb6b822ea775ce388d2844a38ad2608dba67a25683ccec2f8ef' 
  AND token = 'DkSZ6LnCZr7g4uveXl6gUlT2ksfzYlhTs+ilw0vmQiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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