SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a9db8be18dfc02d65379a7335a0888b94fd48cccadc873581c3c224af6be38a2' 
  AND token = 'ue9IFrHh1+EDFGSDFPJzjaCCi4E7JblNP2wXgo0fxo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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