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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3fc42608d9dc2ccbfc055c0986e032013ef3375ef9b3d69b2b6e9e1beb2fa9b2' 
  AND token = 'n70nPTdTd6YpVKdp3pohHvPOk1JQQoWOFdGUyrCtb1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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