SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02b9d20476433b4722407dfbae3954aacaad77c952b0b262df4f69ad742d38da' 
  AND token = 'SUxWHWg0JqO4QcrPl/eJWhpoRbRIiI93+d67s01eC4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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