SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c786a15480611ada1553eb44b2337bf50fe147ad1d557435c028c57d646c4a46' 
  AND token = 'l/kNoHIq/K+4+99d9vBXyKIjjV2vuLtRuD0qtGENPEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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