SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1817c21712cdd4b132980c166fbcf011e6666fcc0ab9ac34e790ebf96647bfa' 
  AND token = 'I0CrntJi3nbnz0Kmp4a/aAr+6XPtb4cgRYRRCIFaY1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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