SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '809ee270d64b3f39d448182119f6d46c2f30099d6531a6d9ad6b08979762fc81' 
  AND token = 'etVBp2mPqBYuTQs/9bv+bDLqucQ8IJDyGJBpy1sMzfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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