SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c6754d14c1c6a39653c735cfb642bc18073d2831fdd91a2a11d04d750c2b736a' 
  AND token = 'KkC6DrmfOPlG5utqAiGUw8jTzwGI19wLbCGb1p40pPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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