SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea4c5396005f1144a689455774df1d7be1946c544ddcc8823c8b76a6e22389bc' 
  AND token = '4zbEBZEVB5SyfQuAbPsUT4Mn/WsMFMazWW4fBFrORco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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