SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e103b74676c73591f50787449b0c77e15afd769ff88c550d0e96bb572c5f146e' 
  AND token = 'igswNXjvsBTInvGar4BoDONJMLAjitrVB1EVNkNQRPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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