SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '615d12885e98825276e8e6012d72e8749e24c0b536fa58c43e41410644213a25' 
  AND token = 'A/BfrmzenN8FsSPuNwWtAIXJpMAfysiIEAhM8kGAPT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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