SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b52295b179f24900d496b9d22ca91bf74c6230e13528580b6e2e8a25ca4fa160' 
  AND token = 't5WlBQBRBi61YXMvlFbzQM1aIdBJjKYZeYM/4tmc+44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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