SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9f766e7e2edea52e982f6cf04e61627d02fc9c0b74652c074cff9e76be64b238' 
  AND token = '6MZRoOYGUBNe5sdxaIN+ixohprPdmjJHVgADOqoJK30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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