SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'af922326c1305d3d8c9f2f1c4a321487e4dbf193e021b50145b2547780ad60ba' 
  AND token = 'ulzFmEnjhIuig1hkqMbto76P7lVBlVpch23/cQP6nB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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