SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '90ffaea7fb044f891857333a877fb2a8dffc7ee8bdf8a956fcae29482bb79df1' 
  AND token = 'PQWEXKE48Bh5KKGZ4GhNgy6b+rBv+nwAiustTPwVXEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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