SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31195a1519893124cdd7fb74dd9a4d790bfcfbe8bcd24cf1b16eb3b24ce482d8' 
  AND token = 'DWS3ESfiKuhp2SQR8VCnBQvaPPsmykGCTTprAWQ3Tro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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