SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb1fec40a4692edfa81849255dc65a663bbef59110f0360d67f9c26976c4440f' 
  AND token = '5hTD+jToGrvbXCwAkCbANE0tPtKuuBQ3BgGlzYCPtvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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