SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a7a9eeb0c2b0acfddb49bb883af605d6cca9111327367e74e5b29f5fd7da739' 
  AND token = 'rzaYKNtZNoMbBtu64BzpciwZPmwAMowRdw74KqQzSVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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