SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2af5594e26aaaf2188f73001fb701b4112e25f0b472db49c6dfbfa258186bb81' 
  AND token = 'CUT+dFtTwwdBgh/bjDgUzNGk713WM57zqrVS2EMmvxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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