SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7428ad6184fa3e52297eee5137b2d964afee4181446606538c9b901761b5f915' 
  AND token = 'YQoHSzfdn44YJH6ET2yyV1+Z7HMkCTDCiT0ICSTsDts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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