SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2ab1e6912cafc29035979fc4f2db90add7e0dd6abac7e143477d1c2b27a307c' 
  AND token = 'RJQdrzMz+bBgdkhPMIVMpXEDx93bhkUZzgrNRENM2+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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