SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe0354a902717618732a379ec2df267ae2f05776a2b51290e4ffda37651c53aa' 
  AND token = '4IbNafcLd1cpxNS1LKwHmTkNTQdzPKykB4t+2GBDJ74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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