SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96e674c1ab848981169ec5bc55521a76eae96e6087dc84d26272151c8f8d5174' 
  AND token = 'UYbv4TmxhAtVOdnuMmtv69yI85t4i31c5LArOdwdryQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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